[Unity quaternion] four-dollar quaternion calculation method

What is quaternion four-dollar number

In 1843, William Rowan Hamilton invented four yuan, but only in 1985 did a man named Ken Shoemake introduce four dollars into the field of computer graphics processing. Four yuan in 3D graphics is mainly used for rotation, skeletal animation and so on.

Simply put, a four-dollar number describes a rotation: rotates one radian (θ) around any axis (V).

Then the four-dollar Q is related to (v,θ) two parameters.

Specific formula:

Q = (sin (θ/2) * V,cos (θ/2))

Q = (sin (θ/2) * X,sin (θ/2) * Y,sin (θ/2) * Z,cos (θ/2))

using the Quaternion object in UnityCreate a Quaternion object

float radians = 90/360f * Mathf.pi * 2;//vector3 n = vector3.up;//float w = mathf.cos (RADIANS/2);//float s = mathf. Sin (RADIANS/2);//float x = n.x * S;float y = n.y * s;float z = n.z * s;//transform.rotation = new quaternion (x, Y, Z, W);

The code above allows you to set a game object to rotate clockwise 90 degrees along the y-axis upward direction.

Methods for quaternion objectsinstance Method

Set usage

float radians = degress/360f * Mathf.pi * 2;//vector3 n = vector3.up;//float w = mathf.cos (RADIANS/2);//float s = M ATHF. Sin (RADIANS/2);//float x = n.x * S;float y = n.y * s;float z = n.z * s;//quaternion q = new quaternion (); Q.set (x, Y, Z, w);//transform.rotation = q;

Setfromratation usage

quaternion q = new quaternion (); Q.setfromtorotation (Vector3.up, vector3.left);//transform.rotation = q;

Setlookrotation usage

quaternion q = new quaternion (); q.setlookrotation (vector3.back);//transform.rotation = q;

Static Methods

Transform.rotation = Quaternion.identity;//transform.rotation = Quaternion.angleaxis (degress, Vector3.up);// Transform.rotation = Quaternion.dot (Q1, q2);//transform.rotation = Quaternion.inverse (q1);//transform.rotation = Quaternion.lerp (q1,q2,time.deltatime);//transform.rotation = Quaternion.slerp (Q1, Q2, time.deltatime);

[Unity quaternion] four-dollar quaternion calculation method